Calculating the electromagnetic field and losses in the end region of large synchronous generators under different operating conditions with three-dimensional transient finite element analysis

Abstract

The significant losses in the end components due to the leakage magnetic field excited by the armature and field end windings can result in partial overheating and is an important consideration in the design of large synchronous generators. This paper describes an approach based on the three-dimensional (3D) transient finite element analysis (FEA) to determine the fields and losses in the generator end region. Taking the nonlinear/anisotropic properties of the stator core, as well as the slitting and stepping shape of core-end packets into consideration, the electromagnetic field and loss distribution in the end region is calculated. The method is validated by the agreement found between the temperatures predicted by the 3D stationary thermal FEA and the temperatures obtained from a physical measurement at various points in the generator. Then, the field and loss distributions in the end region under the open-circuit test condition, power factor lagging condition and leading condition are analyzed and compared using the proposed transient 3D FEA method.